Thread cutting attachment for sewing machines



Oct. 29, 1963 GM. LOBER 3,108,557

THREAD CUTTINQATTACHMENT FOR SEWING MACHINES Filed Dec. 7, 1961 2Sheets-Sheet l INVENTOR Georg e M. L obm' BY KID-MM ATTORNEYS THREADCUTTING ATTACHMENT FOR SEWING MACHINES Filed Dec. '7, 1961 G; M. LOBEROct. 29, 1963 2 Sheets-Sheet 2 8 INVENTOR H George M-LOIDQT'.

BY ATTORNEYS l 9 0 WW ,7 7 4 3 9 J I v M (W 8 Jwmw J a i A 9 UnitedStates Patent 3,108,557 THREAh @UTTENG ATTACHMENT FGR SEWENG MAQHINESGeorge M. Fischer, Saiishury, Nail, assignor to H. Rosenstocl; & Sons,Hno, Ellenviile, NSEL, a corporation of New York Filed Dec. 7, 1961,Ser- No. 157,760 8 Claims. (ill. 1l2-252) This invention relates to theart of sewing, and more particularly to a thread cutting attachmentwhich may be applied to existing sewing machines without alterationthereof, or supplied as standard equipment on newly manufactured sewingmachines.

Heretofore, numerous types of thread-cutting attachments have beenprovided on sewing machines, but many of these required modification ofthe sewing machine to accommodate such attachment, and furthermore, inmany cases, the cutting edge was unprotected, and thereby subject todamage or dulling, and in the main these attachments merely provided ameans for severing the thread, and provided no means for retaining thecut ends of the thread until such time as these ends were manuallyremoved preparatory to a further sewing operation. In view of the usualexposed location of the thread cutting attachments formerly used onsewing machines, in many instances the cutting edges provided wererelatively blunt or dull in order to protect the operator from injury,with the consequence that the thread-severing operation was relativelydifiicult, and often resulted in an undue pulling or strain beingapplied to the thread or material which had been previously sewed.

It is accordingly an object of the invention to provide a thread-cuttingattachment for sewing machines which may be conveniently andeconomically manufactured from readily available materials, and appliedto existing sewing machines without requiring any modification, or whichmay be supplied as an attachment for newly manufactured sewing machines.

A further object of the invention is the provision of a thread-cuttingattachment for sewing machines, including a cutting blade having a keencutting edge, and in which the cutting edge is completely protected fromdamage, and also in which the operator is completely protected againstinjury.

A still further object of the invention is the provision of athread-cutting attachment for sewing machines incorporating a relativelysmall, keen-edged, cutting blade, and in which the cutting blade may beconveniently replaced when the same becomes dull, without the necessityof utilizing tools, or requiring any particulm manual dexterity.

Another object of the invention is the provision of a thread-cuttingattachment for sewing machines, which may be releasably secured to thesewing machine by utilizing the conventional clamp screw, which servesto secure the conventional presser foot to the presser foot bar of thesewing machine, and without in any way interfering with the use orsubstitution of different types of presser feet.

A further object of the invention is the provision of a thread-cuttingattachment for sewing machines which provides for rapid and convenientsevering of the thread in that a throat is provided for guiding thethread into engagement with the edge of the cutting blade, therebyeliminating the necessity for accurate positioning of the thread for thecutting operation.

A still further object of the invention is the provision of athread-cutting attachment for sewing machines, in which means isprovided for resiliently and releasably retaining the severed ends ofthe thread subsequent to amass? Patented et. 29, 1963 2 the cuttingoperation, and until such ends are manually removed from the device.

Another object of the invention is the provision of a thread-cuttingattachment for sewing machines, such attachment comprising only fourparts, including a spring clip for releasably holding the parts inassembled relationship.

Further objects and advantages of the invention will be apparent fromthe following description taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an elevational view showing a thread-cutting attachmentconstructed in accordance with this invention, and installed on thepresser foot bar of a sewing machine, and also showing thethread-cutting operation;

FIG. 2 is a top plan view, with parts in section for greater clarity,and showing the thread-cutting attachment secured to a presser foot bar,and the relationship of the attachment to the conventional presser foot;

FIG. 3, a side elevational view of the thread-cutting attachment removedfrom the sewing machine;

FIG. 4, a sectional view taken substantially on the line 4-4 of FIG. 3;

FIG. 5, a sectional view taken on the line 5--5 of FIG. 3;

FIG. 6, an elevational View showing one of the threadguiding andgripping plates, together with the means provided thereon for securingthe attachment to a sewing machine;

FIG. 7 is a side elevational view showing the other thread-guiding andgripping plate which cooperates with the plate shown in FIG. 6;

FIG. 8, a fragmentary sectional view taken substantially on :the line8-8 of FIG. 9, and showing the manner in which the cut ends of threadare retained in the device after the cutting operation;

FIG. 9, a sectional view taken substantially on the line 9-9 of FIG. 8,and further showing the operation of the plates to grip the cut ends ofthe thread subsequent to the cutting operation; and,

FIG. 10, a view in perspective, showing the resilient clip memberutilized for retaining the parts of the attachment in assembledrelationship.

With continued reference to the drawings, and particularly FIG. 1, thereis shown a vertically disposed presser foot bar lit and a needle 11 of astandard sewing machine, and the presser foot bar lit is provided at thelower end thereof with a fiat portion 12 for engaging the bracketportion of a presser foot 13 in a manner well known in the sewingmachine art, and the presser foot 13 is releasably or removably held inposition by a clamping screw 14 threadedly received in the lower endportion of the presser foot bar 10. Also shown in FIG. 1 is an uppersupporting surface 15 for supporting work during the sewing operation,and a conventional feed dog 16 which operates to feed the work beneaththe presser foot 13 during the sewing operation. The upper thread 17passes through the eye of the needle 11, and the lower thread 18 issupplied from a shuttle below the supporting surface =15, and feedsupwardly through an aperture in alignment with the needle 11. This isall conventional sewing machine construction, and is merely describedfor the purpose of facilitating the description of the structure andoperation of the thread-cutting attachment of this invention.

As best shown in FIGS. 2, 3, 5, 6 and 7, the thread-cutting attachmentof this invention may well comprise a pair of elongated, generallyrectangular opposed thread-guiding and gripping plates 19 and 20, acutting blade 21, and a generally U-shaped, resilient clip member 22partially embracing the plates 19 and 20 and the cutting blade 21 forholding all of the elements in assembled relationship.

With particular reference to FIGS. 5 and 6, the threadgripping andguiding plate 19 may well comprise an elongated, generally rectangularbody portion 23 terminating at the forward end in an outwardly divergingportion 24, and being provided at the rear end with a transverse notch25. Intermediate the ends of the plate 19 is a transverse, elongatedopening 26, and it is to be noted that the end walls 27 and 28 of theopening 26 are V-Shaped. A transverse aperture 29 is provided in theplate 19 between the opening 26, and the outwardly diverging forward end24. inwardly of the notch 25, and adjacent the rear end of the plate 19there is provided an inwardly opening recess 'or aperture 30 in theinner surface, and projecting upwardly from the rear end of the plate 19is an ear 31 having an open ended elongated slot 32 therein forreceiving the clamping screw 14 to secure the plate 19 in position onthe lower end of the presser foot bar 10, and as best shown in FIG. 4,if desired, the car 31 may be offset, as shown at 33, in order toprovide adequate clearance between the plate 19 of the thread-cuttingattachment and the presser foot 13, which is also attached to thepresser foot bar 10, as described above.

As best shown in FIGS. 5 and 7, the thread-guiding and gripping platemay well comprise an elongated, generally rectangular body portion 34terminating at the forward end in an outwardly diverging portion 35, andbeing provided at the rear end with a notch 36, which is of the samegeneral size and configuration as the notch in the rear end of the plate19. Intermediate the ends of the plate 20, there is provided anelongated opening 37, and the end walls 38 and 39 of the opening 37 areV-shaped, and this opening 37 as well as the end walls thereof are ofthe same size and configuration as the opening 26, and end walls 27 and28 thereof in the plate 19. Also provided in the plate 20 between theopening 37 and the diverging end is an aperture 40 of the same size asthe aperture 29 in the plate 19, and inwardly of the notch 36 adjacentthe rear end of the plate 20, there is provided a dimple 'or projection41 of a size tobe received in the recess 30 in the inner surface of theplate 19.

The thread-guiding and gripping plates 19 and 20 are assembled inabutting side-to-side relationship, as shown in FIGS. 2, 3 and 5, anddisposed in the openings 26 and 37 in the plates 19 and 20 is thecutting blade 21 having a cutting edge 43 facing toward the divergingends 24 and 35 of the plates 19 and 20, and as best shown in FIGS. 3 and8, the cutting edge 43 of the blade 21 engages the apexes of theV-shaped end walls as the forward ends of the openings 26 and 37, whilethe rear end 44 of the cutting blade 21 engages the apexes of theV-shaped rear end walls of the openings 26 and 37. This arrangementserves to maintain the cut-ting blade 21 fixed in a substantiallyhorizontal position parallel to the major axes of the plates 19 and 20,and prevents inadvertent displacement of the cutting blade 21. Ifdesired, however, the V-shaped end walls of the openings 26 and 37 couldbe omitted, and the cutting blade 42 positioned loosely therein, or theopenings 26 and 37 provided with dimensions suitable to snugly receivethe cutting blade 21. It will be noted that as shown in FIGS. 5 and 9,the cutting blade 21 is of somewhat greater length than the combinedthickness of the plates 19 and 20.

The plates 19 and 20, as well as the cutting blade 21 are held inassembled relationship by the resilient spring clip 22, which, as bestshown in FIG, 10, is generally U-shaped, being provided with a closedend 45 connecting the legs 46 and 47 thereof, and the leg 46 is providedat the free end thereof with an inturned tab 48, while the leg 47 isprovided at the free end with an inturned tab 48 in alignment with thetab 48. With reference to FIGS. 9 and 10, it will be seen that the legs46 and 47 are provided with outwardly pro- 4 jecting, elongated dimples50 and 51, Which serve to provide inwardly opening elongated recesses 52and 53, the purpose of which will be presently described.

As best shown in FIGS. 3 and 5, the resilient clip member 22 partiallyembraces the plates 19 and 20, with the closed end 45 of the clip member22 received in the aligned notches 25 and 36, the legs 46 and 47extending forwardly in engagement with the outer surfaces of the plates19 and 21), and with the inturned tabs 48 and 49 received in theapertures 40 and 29, respectively, to prevent inadvertent displacementof the clip 22. The engagement of the dimple or projection 41 on theinner surface of the plate 20 in the recess or aperture 30 in the innersurface of the plate 19 serves to align the rear ends of the plates 19and 20 with the notches 25 and 36 in alignment, and also with theopenings 26 and 37 in alignment. The dimple 41 and re cess or aperture30 may, if desired, be omitted or other suitable means for maintainingthe plates 19 and 20 in alignment may be utilized. The engagement of thetabs 48 and 49 in the apertures 40 and 29 serve to retain the forwardends of the plates 19 and 35 in substantial alignment. Since the leg 46and 47 of the clip member 22 cover the outer ends of the openings 37 and26, respectively, the cutting blade 21 is retained therein with theprojecting ends of the blade 21 received in the recesses 52 and 53, asshown in FIG. 9, and inadvertent displacement or removal thereof isprevented. If, however, it is desired to remove or renew the cuttingblade 21, it is only necessary to remove the resilient clip member 22,which serves to expose the openings 26 and 37, to permit convenientremoval of the blade 21, and replacement thereof by a new or sharpenedblade.

Since the thread-guiding and gripping plates 19 and 26 are assembled inface-to-face abutting relationship, the outwardly diverging ends 24 and35 thereof will pro-' vide a thread receiving and guiding throat 54between these diverging ends, and in the use of the thread-cuttingattachment of this invention, it is assumed that as shown in FIG. 1, agarment or other workpiece has been provided with a seam or other lineof sewing in a conventional manner, and the garment or workpiece 55 witha chain of stitching 56 attached thereto and leading from the upper andlower threads 17 and 18 is pulled outwardly a sufiicient distance topermit reception of the chain 56 or the threads 17 and 18 into thethroat 54 between the plates 19 and 20, and rearward movement of thethread between the plates 19 and 29 will result in slightly spreadingthe same against the action of the resilient clip member 22, as clearlyshown in FIGS. 1, 8 and 9, until the thread engages the cutting edge 43of the cutting blade 21, which will result in severing the thread atthis point. The chain 56, or portions of the threads attached to thegarment 55 may then be manually removed from between the plates 19 and20, and the ends of the threads 17 and 18 still received between theplates 19 and 20 will be releasably held in this position until removedby the operator, or until the com mencement of the succeeding sewingoperation. This retaining action of the plates 19 and 20 preventsinadvertent removal of the upper thread 17 from the eye of the needle11, or inadvertent loss of the lower thread 18 through the opening inthe supporting surface 15 to the underside of the machine. Furthermore,by reason of the excess length of the blade 21 over the com binedthickness of the plates 19 and 20, these plates may spread a sufiicientdistance to accommodate any commonly used size or gauge of thread, andat the same: time provide adequate support for the blade 21.

it will be seen that by the above described invention, there has beenprovided an extremely simple, yet highly effective threadcuttingattachment for sewing machines which may be conveniently attached to asewing machine, or removed therefrom merely by manipulation of thepresser foot clamping screw 14, and without requiring any modificationof the sewing machine, or in any way interfering with the normalattachments applied thereto or the operation thereof.

The device comprises only four parts which are releasably held inassembled relationship by the resilient clip member 22, and the cuttingblade 21 may be conveniently replaced when dull or otherwiseinoperative, and it is further to be noted that the cutting blade 21 iscompletely protected from inadvertent damage, and is also positioned insuch a manner as to preclude injury to the operator. The constructionand design of the thread-cutting attachment of this invention permitsmanufacture and sale thereof for attachment to existing sewing machineswithout any modification whatsoever, or the device may be applied to newsewing machines as standard equipment thereon.

It will be obvious to those skilled in the art that various changes maybe made in the invention without departing from the spirit and scopethereof, and therefore the invention is not limited by that which isshown in the drawings, and described in the specification, but only asindicated in the appended claims.

What is claimed is:

1. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated, generally rectangular opposed threadguiding and gripping plates, said plates diverging at one end to providea thread-guiding throat, said plates having aligned elongated openingsdisposed lengthwise thereof, a cutting blade disposed in said openingswith the cutting edge facing toward said diverging ends, the length ofsaid blade being greater than the combined thickness of said plates, theopposite ends of said plates aligned transverse notches, said plateshaving aligned transverse apertures therein between said openings andsaid diverging ends, a clip for yieldably holding said plates in opposedface-to-face relationship and for retaining said blade in said openings,said clip comprising a generally U-shaped resilient member having legsembracing a portion of said plates with the closed end of said memberreceived in said notches and inturned tabs on the free ends of said legsreceived in said apertures to prevent inadvertent displacement of saidmember, inwardly opening recesses in said legs for receiving theprojecting ends of said blade, and means on one of said plates forremovably mounting the same on the presser foot bar of a sewing machine,said last-named means comprising an ear projecting from said one plate,said ear having a slot for receiving a clamping screw, whereby uponpulling a thread into said throat between said plates and intoengagement with said blade, said thread will be severed, the ends of thecut thread being releasably retained between said plates.

2. A thread-cutting attachment for sewing machines as defined in claim1, in which one of said plates is provided with a recess in the innersurface adjacent the notched end, the other plate having a projection onthe inner surface adjacent the notched end, said projection beingreceived in said recess to maintain said plates in alignment.

3. A thread-cutting attachment for sewing machines as defined in claim1, in which the end walls of said openings are V-shaped to engage andretain said blade substantially parallel to the major axis of saidplates.

4. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated generally rectangular opposedthread-guiding .and gripping plates, said plates diverging at one end toprovide a threadguiding throat, said plates having aligned elongatedopenings disposed lengthwise thereof, a cutting blade disposed in saidopenings with the cutting edge facing toward said diverging ends, thelength of said blade being greater than the combined thickness of saidplates, the opposite ends of said plates having aligned transversenotches, said plates having aligned transverse apertures 6 thereinbetween said openings and said diverging ends, a clip for yieldablyholding said plates in opposed faceto-face relationship and [forretaining said blade in said openings, said clip comprising a generallyU-shaped resilient member having legs embracing a portion of said plateswith the closed end of said member received in said notches and inturnedtabs on the free ends of said legs received in said apertures to preventinadvertent displacement of said member, inwardly opening recesses insaid legs for receiving the projecting ends of said blade and means onone of said plates for removably mounting the same on the presser tootbar of a sewing machine, whereby upon pulling a thread into said throatbetween said plates and into engagement with said blade, said threadwill be severed, the ends of the cut thread being releasably retainedbetween said plates.

5. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated generally rectangular opposedthread-guiding and gripping plates, said plates diverging at one end toprovide a thread-guiding throat, said plates having aligned elongatedopenings disposed lengthwise thereof, a cutting blade disposed in saidopenings with the cutting edge facing toward said diverging end-s, saidplates having aligned transverse apertures therein between said openingsand said diverging ends, a clip for yieldably holding said plates inopposed face-toface relationship and for retaining said blade in saidopenings, said clip comprising a generally U-shaped resilient memberembracing a portion of said plates with the closed end of said memberdisposed opposite said diverging ends and inturned tabs on the free endsof said member received in said apertures to prevent inadvertentdisplacement of said member and means on one of said plates forremovably mounting the same on the presser foot bar of a sewing machine,whereby upon pulling a thread into said throat between said plates andinto engagement with said blade, said thread will be severed, the endsof the out thread being releasably retained between said plates.

6. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated generally rectangular opposedthread-guiding and gripping plates, said plates diverging at one end toprovide a threadguiding throat, said plates having aligned elongatedopenings disposed lengthwise thereof, a cutting blade disposed in saidopenings with the cutting edge facing toward said diverging ends, a clipfor yieldably holding said plates in opposed .face-to-face relationship,and for retaining said blade in said openings, said clip comprising agenerally U-shaped resilient member embracing a portion of said plateswith opposed end of said member disposed opposite said diverging ends,means to prevent inadvertent displacement of said member and means onone of said plates for removably mounting the same on the presser footbar of a sewing machine, whereby upon pulling a thread into said throatbetween said plates and into engagement with said blade, said threadwill be severed, the ends of the cut thread being releasably retainedbetween said plates.

7. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated generally rectangular opposedthread-guiding and gripping plates, said plates diverging at one end toprovide a threadguidin-g throat, said plates having aligned elongatedopenings disposed lengthwise thereof, a cutting blade disposed in saidopenings with the cutting edge facing toward said diverging ends, a clipfor yieldably holding said plates in opposed face-to-face relationshipand for retaining said blade in said openings, said clip comprising agenerally U-shaped resilient member embracing a portion of said plateswith the closed end of said end of said member disposed opposite saiddiverging ends, means to prevent inadvertent displacement of said memberand mounting means for said attachment, whereby upon pulling a threadinto said throat between said plates and into engagement with saidblade, said thread will be severed, the ends of the cut thread beingreleasably retained between said plates.

8. A thread-cutting attachment for sewing machines, said attachmentcomprising a pair of elongated generally rectangular opposedthread-guiding and gripping plates, said plates diverging at one end toprovide a threadguiding throat, said plates having aligned elongatedopenings disposed lengthwise thereof, a cutting blade removably disposedin said openings with the cutting edge facing toward said diverging endsand detachable biasing means for yieldably holding said plates inopposed facetoface relationship and for retaining said blade in saidReferences Cited in the file of this patent UNITED STATES PATENTSSilver-man July 12, 1949 Klapper Jan. 6, 1959 OTHER REFERENCES IBMTechnical Disclosure Bulletin, Vol. 2, No. 1, June 1959, page 8. (Copyavailable in Div. 11.)

1. A THREAD-CUTTING ATTACHMENT FOR SEWING MACHINES, SAID ATTACHMENTCOMPRISING A PAIR OF ELONGATED, GENERALLY RECTANGULAR OPPOSED THREADGUIDING AND GRIPPING PLATES, SAID PLATES DIVERGING AT ONE END TO PROVIDEA THREAD-GUIDING THROAT, SAID PLATES HAVING ALIGNED ELONGATED OPENINGSDISPOSED LENGTHWISE THEREOF, A CUTTING BLADE DISPOSED IN SAID OPENINGSWITH THE CUTTING EDGE FACING TOWARD SAID DIVERGING ENDS, THE LENGTH OFSAID BLADE BEING GREATER THAN THE COMBINATED THICKNESS OF SAID PLATES,THE OPPOSITE ENDS OF SAID PLATES ALIGNED TRANSVERSE NOTCHES, SAID PLATESHAVING ALIGNED TRANSVERSE APERTURES THEREIN BETWEEN SAID OPENINGS ANDSAID DIVERGING ENDS, A CLIP FOR YIELDABLY HOLDING SAID PLATES IN OPPOSEDFACE-TO-FACE RELATIONSHIP AND FOR RETAINING SAID BLADE IN SAID OPENINGS,SAID CLIP COMPRISING A GENERALLY U-SHAPED RESILIENT MEMBER HAVING LEGSEMBRACING A PORTION OF SAID PLATES WITH THE CLOSED END OF SAID MEMBERRECEIVED IN SAID NOTCHES AND INTURNED TABS ON THE FREE ENDS OF SAID LEGSRECEIVED IN SAID APERTURES TO PREVENT INADVERTENT DISPLACEMENT OF SAIDMEMBER, INWARDLY OPENING RECESSES IN SAID LEGS FOR RECEIVING THEPROJECTING ENDS OF SAID BLADE, AND MEANS ON ONE OF SAID PLATES FORREMOVABLY MOUNTING THE SAME ON THE PRESSER FOOT BAR OF A SEWING MACHINESAID LAST-NAMED MEANS COMPRISING AN EAR PROJECTING FROM SAID ONE PLATE,SAID EAR HAVING A SLOT FOR RECEIVING A CLAMPING SCREW, WHEREBY UPONPULLING A THREAD INTO SAID THROAT BETWEEN SAID PLATES AND INTOENGAGEMENT WITH SAID BLADE, SAID THREAD WILL BE SERVED, THE ENDS OF THECUT THREAD BEING RELEASABLY RETAINED BETWEEN SAID PLATES.